QuestionI just purchased new Michelins for my Passat. They are premium grade with
AAA wear ratings. The tire store aligned the wheels at time of purchase, but
all 4 tires are showing extra wear on the inside and outside treads of the tire.
When I went back the dealer said Michelins always wear more on the inner
and outer walls of time. I've never had this problem before when purchasing
Michelin tire for my other cars. Would this kind of problem happen if the
tires are the wrong size for the car or somethings was done incorrectly on all
wheels when aligned. Thanks for any tips that may explain what is going on.
- Frank
AnswerFrank,
What inflation pressure are you using? Not enough can cause both shoulders to wear.
On every vehicle sold in the US, there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size. The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.
Personally, I like a car that handles crisply. So I use 3 to 5 psi above the placard pressure. I also get better fuel economy, better wet traction, better snow traction, better tire durability, better tire wear, but I do have a degradation in ride harshness (but I am willing to put up with it.)
BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.
If you are using a tire size that is different than what is listed on the placard, then the pressure has to be recalculated. The calculation is not difficult, but it requires tire load tables which are not allowed to be published in the Internet because of copywrite laws. However, I have a copy and would be glad to do the calculation, but the starting point is the vehicle placard: Tire size and inflation pressure. I will also need to know the new tire size.
